Heat the ingredients in a small or medium covered saucepan, over high heat. When the sauce starts to boil, slightly reduce heat to medium-high and leave the lid ajar. Continue cooking for another 15-20 minutes. In the meantime, bring a large pot of salted water to a boil and cook the pasta according to package instructions. Discard the onion from the sauce and toss with well drained pasta. Sprinkle a couple of handfuls of your choice of grated Italian cheese and serve. MAKES 4-6 SERVINGS